Detective Harry Morgan (James Remar) is the adoptive father of forensic blood-spatter analyst Dexter Morgan (Michael C. Hall). Realizing that Dexter has been psychologically damaged after witnessing his mother's brutal murder, Morgan resolves to raise him by shaping and controlling the sociopathic "Dark Passenger" within. He teaches Dexter the "Code of Harry, " which involves acting as a vigilante to hunt and kill murderers without leaving any evidence, while putting on a front of normalcy. Morgan's biological daughter Debra (Jennifer Carpenter) is unaware of Dexter's true nature and the Code of Harry, but her admiration for her father inspires her to become a homicide detective. Although long deceased, Morgan remains highly influential in Dexter's life, appearing through ghostly flashbacks to offer advice and guidance.
"Remember this forever, you are my son, you are not alone, and you are loved."
"Son, there are people out there who do really bad things. Terrible people. And the police can't catch them all. Do you understand what I'm saying?"